Minutes of IR FEL Mechanical Systems Meeting, February 29, 1996

NOTE: Meetings are held every Thursday in Trailer City, Room 84, at 1 p.m., unless otherwise notified.

ATTENDEES: S. Benson, G. Biallas, J. Bisognano, C. Bohn, J.C. Denard, D. Douglas, L. Harwood, K. Jordan, C. Murray, G. Neil, J. Parkinson, M. Wiseman.

Decisions/Comments:

The vacuum near cryomodules could be relaxed from 3x10-9 Torr such that baking may not be necessary. The proposed vacuum pumping will achieve 10-8 Torr with conventional cleaning methods.

D. Douglas reports that the design of the wiggler-downstream option seems to be converging. The design uses 7 more quads for the drift regions, is narrower than the Dec. design and will use end dipoles with a 1.25 m. radius rather than 1 m. He recommended going ahead with roughing in the designs of end magnets, and the quads and ordering the material for the end magnets on that basis. We will proceed accordingly.

Slots from beam pipe to vacuum pump region may be too wide in the present design of the shielded beam viewer.

Action Items:

G. Biallas/J. Parkinson - Do the appropriate calculations and get Sign-off on relaxed vacuum requirements near cryomodule by R. Sundelin & P. Kneisel. We need the hard interlock values for closing valves.

D. Douglas - Add the bunch lengths to zones on the layout drawing so impedance issues can be assessed.

C. Murray - Add a 6 inch wide tube to the chamber intersections at the injection crotch, dump crotch and laser mirror ports.

C. Murray/D. Douglas - Shift the injector upstream to the correct origin, shorten the magnets to 2/5 length and make the magnets wedge style.

C. Murray - Add cookie cutter beam tube transitions to all positions that have a tube going from large to small.

J. Parkinson - Find out how effective the electrostatic precipitator at the front end of the first linac was.

S. Benson/R. Boies - Layout the proposed Optical Cavity

J. Bisognano/B. Yunn - Make a list of impedance issues and begin analyses. Known issues discussed to date include impedances of the crotch chambers associated with the wiggler, and vacuum-pipe transitions.